It’s awesome your wife wants to get into this industry. With her passion, I have no doubt she’ll help change lives.
There are CPT courses(certified personal trainer) and then they’re specialty certifications offered as continuing education.
Her ISSA or NASM certification will provide the baseline knowledge, then she can get certified in say NASM’s Performance Enhancement Specialist(PES) course to expand her knowledge in sports training.
If you browse through the ISSA, NASM, NSCA, ACSM, ACE sites you can see what other specialty courses they offer. What they have to offer might determine what certification organization she goes through.